Large-scale networks used for cloud computing, search engines, and similar applications, typically include tens or hundreds of servers for load sharing and for redundancy. These networks need to be highly scalable, so there is a need to frequently add more servers to the network infrastructure.
Large-scale server networks consume very large amounts of electric power and generate a lot of heat. Any manner of reducing power consumption is desirable.
Many servers in large-scale server networks required AC power. Fuses and/or relays may be used to cut delivery of AC power to a server in case of a fault, for example in the occurrence of a short-circuit. However fuses are typically slow to react and must be replaced after a short-circuit. Relays may protect a server from a short-circuit, and may be rearmed, but are very slow to react. Additionally, AC current that is provided to a server must flow through contacts of a relay, causing important power losses. Measurements have shown that, typically up to 4% of the power delivered to a server may be lost in a relay. The energy wasted in the relay causes heat accumulation in the power supply that, for a large server bank, translates into important cooling needs.
Eventual loss of a server in a large-scale server network can be compensated when sufficient redundancy is provided in the network. The loss of one power distribution unit (PDU) may however have significant impact when it causes the concurrent loss of a plurality of servers connected thereto.
Availability requirements for large-scale server networks are extremely high, so maintenance activities, including connection of additional servers and replacement of failed units must be done without delay and without service disruption.
Even though the recent developments identified above may provide benefits, improvements are still desirable.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches.